Boffins trial cheap landmine sniff-tech

American boffins reckon they may have found a way to build landmine-detecting equipment more cheaply, possibly offering hope to dispossessed people in warzones around the world.

Landmines are cheap to make and easy to lay. Once laid, they are difficult and dangerous to clear up: so much so that minefields often become effectively permanent. Productive farmland can pass out of use, even when a given conflict is over, and people lose their homes and livelihoods forever. It's not so much that the mines can't be cleared, just that it doesn't make economic sense to do it.

Part of the problem lies in the cost of detecting buried mines. A lot of the more modern ones are largely non-metallic in construction, deliberately hard to find with basic metal-detecting magnetic gear. There are other methods which can find them safely, but they mostly involve expensive hardware. Examples include ground-penetrating radars, for instance. That's OK for a well-funded Western military or contractor clearance team, looking maybe to open up an important route.

It won't do, though, for a Third-World villager needing to clear a few fields to get some crops planted. His farm will never make enough money to pay for the use of complex gear; he needs something a lot cheaper. A surprisingly good job can be done with eyes and a thin metal probe, but if the mines have been buried for a long time these methods become very dangerous, to the point where it's hard for one person to clear enough ground to support a family before getting killed (or, more likely, crippled in some way). The equation of blood, money, and land can be impossible to solve.

Enter Gregg Larson and James Martin of the Georgia Institute of Technology. They report that it's possible, at least in a laboratory environment, to detect buried landmines using a relatively cheap acoustic system.

According to their report, published this month: "Commercially available microphones were investigated as near-ground sensors... images formed using microphone data collected in a laboratory experimental model clearly locate buried inert landmines but exhibit more clutter than images of the same objects formed with seismic displacement data collected using other techniques."

Larson and Martin's techniques could offer a basis for a more affordable sensor system, cutting the cost of landmine clearance. Charities and NGOs could clear more area for the same money, and a loan that a small farm could afford might suffice to clear it in the first place. A bit of extra display clutter might be worth putting up with, in that kind of scenario.

NewScientistreports that the microphones in question could cost as little as $65, compared to radar imaging gear with a pricetag in the thousands. ®